Miniature push-button electrical switch with insertable stationary contact mounting means

ABSTRACT

The illustrated electrical switch comprises an insulating push button or pin which is axially slidable in a guide opening formed in an insulating housing or case. A contactor in the form of a metal disc is mounted on the pin and is engageable with a stop shoulder which is also engageable with an end wall on the housing to limit the outward movement of the pin. A coil spring is mounted around the pin and is compressed between the contactor and an insulating insert mounted in the housing. The contactor is engageable with the inwardly slanting end portions of a pair of contact strips confined between the insert and the outer shell of the housing. The spring normally biases the contactor into engagement with the contacts. The insert is retained within the outer shell of the housing by a barb which is formed on the insert and is receivable in an opening formed in the outer shell.

[ MINIATURE PUSH-BUTTON ELECTRICAL SWITCH WITH INSERTABLE STATIONARY CONTACT MOUNTING MEANS Andrew F. Raab, Morton Grove, Ill.

Indak Manufacturing Corp., Northbrook, 11].

Filed: Oct. 30, 1972 Appl. N0.: 302,031

[75] Inventor:

[73 Assignee:

us. 01. 200/159 n, 200/159 A m. c1. 110111 13/52, 110111 13/10 Field of Search 200/159 1-1, 159 R [56] References Cited UNITED STATES PATENTS 10/1951 Hafke 200/159 R X 3/1965 Fiddler 200/159 A 6/1964 Dow et a1. 200/159 A X 5/1932 Norviel 200/159 R Mar. 12, 1974 Primary ExaminerRobert K. Schaefer Assistant ExaminerRobert A. Vanderhye 5 7] ABSTRACT The illustrated electrical switch comprises an insulating push button or pin which is axially slidable in a guide opening formed in an insulating housing or case. A contactor in the form of a metal disc is mounted on the pin and is engageable with a stop shoulder which is also engageable with an end wall on the housing to limit the outward movement of the pin. A coil spring is mounted around the pin and is compressed between the contactor and an insulating insert mounted in the housing. The contactor is engageable with the in wardly slanting end portions of a pair of contact strips I confined between the insert and the outer shell of the housing. The spring normally biases the contactor into engagement with the contacts. The insert is retained within the outer shell of the housing by a barb which is formed on the insert and is receivable in an opening formed in the outer shell.

1 Claim, 10 Drawing Figures MINIATURE PUSH-BUTTON ELECTRICAL SWITCH WITH INSERTABLE STATIONARY CONTACT MOUNTING MEANS This invention relates to electrical switches and is particularly applicable to miniature push-button electrical switches.

One object of the present invention is to provide an electrical switch construction which is well adapted for producing an efficient and highly dependable pushbutton switch which is extremely small in size.

A further object is to provide a new and improved switch having a minimum of components which are extremely small in size, yet which are constructed and arranged to produce a switch capable of providing dependable operation over an extremely long life.

To achieve these objects, the switch of the present invention preferably comprises a pin or plunger which is slidable in a guide opening formed in a housing or case. A contactor is mounted on the pin and is movable therewith. The contactor is adapted to be engaged with a pair of resilient contacts having end portions inclined inwardly toward the pin so as to be disposed in the path of the contactor.

A spring is preferably provided to bias the contactor and the pin into a position in which the contactor engages the contacts. The pin has a portion which projects out of the housing and may be depressed to move the contactor out of engagement with the contacts. The spring is preferably in the form of a coil spring mounted on the pin and compressed between the contactor and a stationary portion of the housing.

Such portion may be in the form of an insert mounted within the outer shell of the housing.

The spring preferably biases the contactor against a stop element on the pin. Such stop element also preferably engages another stop element on the housing to limit the outward travel of the pin. The contacts are preferably in the form of metal strips having portions confined between the insert and the outer shell. The contact strips extend along opposite sides of the pin and are spaced outwardly therefrom. The end portions of the strips slant inwardly toward the pin for engagement by the contactor disc. The insert is preferably slip-fitted into the outer shell and is retained therein by a barb which'is formed on the insert and is receivable in an opening formed in the outer shell.

Further objects, advantages and features of the present invention will appear from the following description, taken with the accompanying drawings, in which:

FIG. 1 is an elevational view showing a miniature push-button electrical switch to be described as an illustrative embodiment of the present invention.

FIG. 2 is an enlarged sectional exploded view of the switch.

FIG. 3 is a greatly enlarged longitudinal section of the assembled switch.

FIGS. 4, 5, 6, 7, 8 and 9 are cross sections taken through the switch, generally along the lines 44, 55, 6-6, 7 -7, 8-8 and 9'9 in FIG. 3.

FIG. 10 is a greatly enlarged fragmentary plan view, taken generally as indicated by the line 10-10 in FIG. 1.

FIG. 1 illustrates the external appearance of a miniature push-button electrical switch 12, comprising a push button or pin 14 which is axially slidable in a housing or case 16. Both the pin 14 and the housing 16 are preferably made of some suitable electrically insulating material, such as a suitable plastic material which can be molded inexpensively into the desired shape.

Electrical connections are made to the switch 12 by a pair of insulated electrical leads or wires 18. One end of each lead 18 extends into the housing 16. In this case, the opposite ends of the leads 18 extend into a connector 20 having a pair of contacts 22 which are connected to the leads 18.

The electrical switch 12 is preferably of a very small or miniature size and is shown approximately full size in FIG. 1.

The miniature push-button switch 12 will find many applications, particularly to perform various control functions on vehicles. Thus, for example, the switch may be employed as a brake light switch or as a door switch.

The illustrated housing or case 16 is generally cylindrical in shape. To assist in mounting the switch, the illustrated housing 16 is formed with an external locating groove 24 which extends longitudinally along a portion of the housing 16, and a transverse locating notch 26.

To assist in the assembly of the switch 12, the housing 16 preferably comprises an outer shell 28 and an insert or body 30 adapted to be mounted within the shell 28. Both the shell 28 and the insert 30 are preferably made of electrically insulating material.

The push-button or pin 14 is preferably in the form of a generally cylindrical rod which is slidable within one or more guide openings in the housing 16. In this instance, the outer shell 28 has an end wall 32 which is formed with one such guide opening 34. An aligned guide opening 36 is formed axially in the insert 30.

The pin 14 preferably has a stop element in the form of an annular shoulder or ridge 38, projecting outwardly from the pin near its mid point. The shoulder 38 is engageable with the end wall 32 to limit the outward movement of the pin 14.

It will be seen from FIGS. 2 and 3 that the pin 14 acts as a carriage to support an electrically conductive contactor 40 which is preferably in the form of a metal disc slidably received around the inner portion of the pin 14 behind the shoulder 38. A spring-42 is preferably provided to bias the contactor 40 and the pin 14 in one direction. In this instance, the spring 42 is in the form of a compression coil spring acting between the insert 30 and the contactor 40. The spring 42 biases the contactor 40 against the stop shoulder 38, which is thereby biased against the end wall 32 which acts as a stop on the housing 16.

Electrical contacts 44 are provided within the housing 16 for engagement by the contactor 40. It is preferred to provide a pair of such contacts 44 spaced outwardly from the pin 14 at diametrically opposite points. The contacts 44 preferably have end portions 46 inclined inwardly toward the pin 14 for engagement by the contactor 40.

As shown, the contacts 44 are in the form of conductive metal strips extending generally parallel to the pin 14 and spaced outwardly therefrom by a sufficient distance to afford clearance from the contactor 40. The end portions 46 slant inwardly into the path of the contactor 40.

The spring 42 is preferably arranged so that it biases the contactor 40 into engagement with the slanting end portions 46 of the contacts 44. Thus, the switch 12 is normally closed in that the contactor 40 completes an electrical circuit between the contacts 44. The switch may be opened by depressing the pin or plunger 14 so as to move the contactor 40 out of engagement with the slanting end portions 46 of the contactors 44. It will be understood that the construction of the switch may be rearranged so that the switch is normally open, rather than normally closed.

In the illustrated construction, the contact strips 44 are confined between the outer shell 28 and the insert 30, both of which are preferably made of a suitable plastic or some other electrically insulating material. The illustrated insert 30 has a pair of flat surfaces 48 against which the contact strips 44 are mounted. Notches 50 are formed in the insert 30 along the edges of the flat surfaces 48 to receive locating prongs or flanges 52 bent laterally from the contact strips 44.

It will be seen from FIG. 3 that a chamber or space 54 is formed in the outer shell 28 in front of the insert 30. The front portions of the contact strips 44 project into this space 54 and terminate in the inwardly slanting end portions 46. The front portions of the contact strips 44 are loosely confined by locating flanges 56 projecting into the space 54 from the outer shell 28. As shown in FIG. 2, the inwardly slanting end portions 46 of the contact strips 44 are of a reduced width so that they are freely movable between the flanges 56. Thus, the contact strips 44 are free to yield slightly when engaged by the contactor 40 so that the contactor will come into firm engagement with both contact strips 44.

The leads or wires 18 are suitably connected to the contact strips 44. As shown in FIGS. 2, 3 and 8, each contact strip 44 has a terminal portion 58 at its rear end. Each terminal portion 58 may comprise a pair of flanges or lugs 60 which are wrapped around and clinched against the conductors 62 of the insulated leads 18. In this way, the conductors 62 are securely clamped to the contact strips 44. The insulation is stripped off the ends of the leads 18 so that the conductors 62 are exposed. In this way, the conductors 62 can be clamped within the terminal portions 58 of the contact strips 44.

The terminal portions 58 and the adjacent portions of the insulated leads 18 are received between the insert 30 and the outer shell 28. In the illustrated construction, the insert 30 is formed with longitudinal grooves 64 which are cylindrically curved in cross section to receive the terminal portions 58 and the leads 18.

The rear portion of the chamber 54 within the outer shell 28 is shaped to receive the insert 30 with the contact strips 44 and the leads 18 mounted thereon. The shape of the insert 30 is noncircular so that it will not rotate within the outer shell 28.

Interlocking elements are preferably provided to retain the insert 30 within the shell 28. As illustrated, such interlocking elements comprise a barb 66 and an opening 68. It is preferred to form the barb 66 on the insert 30, while the opening 68 is preferably formed in the outer shell 28. However, this situation could be reversed. The barb 66 is slanted so that it is easy to slide the insert 30 into the outer shell 28, which flexes outwardly to admit the barb. When the barb 66 comes into alignment with the opening 68, the adjacent portion of the outer sheel 28 snaps behind the barb 66 so that the insert 30 will be securely retained within the outer shell 28.

Initially, when the pin or plunger 14 is not depressed, the spring 42 biases the contactor 40 into engagement with the slanting end portions 46 of the contacts 44. When the pin 14 is pressed rearwardly, the shoulder 38 carries the contactor 40 rearwardly against the biasing action of the spring 42 so that the contactor is moved out of engagement with the contacts 44 as shown in broken lines in FIG. 3.

The size of the switch 12 is very small, but the cross section of the contacts 44 is ample to conduct a large electrical current. The contactor 40 has a wiping action against the slanting end portions 46 of the contact strips 44 so that good electrical contact is assured between the contactor and the contacts.

The contacts 44 are sufficiently resilient to insure that the contactor 40 will make good contact with both contacts 44. Thus, the operation of the switch is highly reliable.

I claim:

1. An electrical switch,

comprising a housing,

including a hollow generally cylindrical outer shell made of electrically insulating material and having an integral endwall formed with a first axial guide opening,

said housing including an insert made of electrical insulating material and closely received within said outer shell,

said insert having a second axial guide opening therein aligned with said first axial guide opening,

an operating pin slidably mounted in said first and second guide openings,

said pin having a shoulder thereon engageable with the inner side of said endwall,

a conductive contactor disc mounted on said pin for movement therewith,

a compression coil spring mounted on said pin between said contactor disc and said insert for biasing said shoulder against said endwall,

said contactor disc being disposed between said spring and said shoulder,

and a pair of resilient contact strips made of sheet metal and mounted in said housing on opposite sides of said pin,

said contact strips having first end portions near side endwall and angling inwardly toward said pin for engagement by said contactor disc to complete an electrical circuit between said contact strips,

said contact strips having second end portions confined between said insert and said outer shell of said housing,

said second end portions having pairs of flanges projecting inwardly therefrom,

said insert having notches therein interlocking with said flanges to retain said contact strips between said insert and said outer shell,

said insert having an outwardly projecting barb thereon,

said outer shell having an opening therein for receiving and interlocking with said barb to retain said insert within said outer shell,

said barb having a sloping ramp surface for engaging said outer shell to provide for easy insertion of said insert into said outer shell.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,79 4] Dated March 12, 197M.

Inventor(s) Andrew F. Raab It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column L line 1 5, after "near" change "side" to said Signed arid sealed this 18th day of June 19714.;

(SEAL) Attest:

EDWARDMT ETCHE JRT I c. MARSHALL .DANN

Attesting Officer 'Actesting Officer FORM PC4050 $69) uscoMM-oc 603745.969 v ILS. GOVERNMENT PRINTING OFFICE t 1969 0*365-554, 

1. An electrical switch, comprising a housing, including a hollow generally cylindrical outer shell made of electrically insulating material and having an integral endwall formed with a first axial guide opening, said housing including an insert made of electrical insulating material and closely received within said outer shell, said insert having a second axial guide opening therein aligned with said first axial guide opening, an operating pin slidably mounted in said first and second guide openings, said pin having a shoulder thereon engageable with the inner side of said endwall, a conductive contactor disc mounted on said pin for movement therewith, a compression coil spring mounted on said pin between said contactor disc and said insert for biasing said shoulder against said endwall, said contactor disc being disposed between said spring and said shoulder, and a pair of resilient contact strips made of sheet metal and mounted in said housing on opposite sides of said pin, said contact strips having first end portions near side endwall and angling inwardly toward said pin for engagement by said contactor disc to complete an electrical circuit between said contact strips, said contact strips having second end portions confined between said insert and said outer shell of said housing, said second end portions having pairs of flanges projecting inwardly therefrom, said insert having notches therein interlocking with said flanges to retain said contact strips between said insert and said outer shell, said insert having an outwardly projecting barb thereon, said outer shell having an opening therein for receiving and interlocking with said barb to retain said insert within said outer shell, said barb having a sloping ramp surface for engaging said outer shell to provide for easy insertion of said insert into said outer shell. 